You didn't specify what year that you have but most parts manual will have them listed for your particular year.If you don't have a manual, i'd suggest picking one up.If that's not a possibility call your favorite parts supplier(s) and maybe they'll look it up for you.Go to the local industrial parts supplier and buy a variety and see what fits.Measure holes and thread count for a closer guess.

Harley-Davidson was particularly fond of using 5/16x32 threaded grease fittings. A non standard size. Most aftermarket suppliers can get them.From your post I get the impression you are not in America. Where are you?Robbie